1. Field of the Invention
The invention concerns a noise-suppression capacitor which is integrally manufactured within or upon a brush in an electric motor.
2. Related Art
Brush-type electric motors generate electrical arcing when the brushes contact the commutator. This arcing acts as a source of electrical noise and can interfere with electronic devices. For example, automobiles contain numerous motors, such as in heating and cooling fans, seat-adjustment motors, window motors, and so on. The electrical noise can interfere with cellular telephones, global navigation-positioning systems, entertainment systems, and other devices.
As the numbers and types of electronic devices used in automobiles increases, the problems created by the noise is expected to also increase.
In one form of the invention, a brush for an electric motor contains a series inductor and a shunt capacitor integrally formed into the brush.
An object of the invention is to provide an improved electric motor.
In one aspect, this invention comprises a brush for an electric motor, comprising a block for contacting a commutator, a plurality of conductors extending from the block, and a conductive sheath surrounding each conductor and connected to ground, wherein each sheath-conductor pair forms a capacitor.
In another aspect, this invention comprises a brush for an electric motor, comprising a contact for contacting a commutator in the motor, an inductor, connecting with a contact, and a block of material which supports a contact and encases said inductor.
In still another aspect, this invention comprises a brush for an electric motor, comprising a contract for contacting a commutator in the motor, an inductor, connecting with said contact, a block of material which supports a contact and encases an inductor and a capacitor which connects between a contact and an external lead and is encased in a block.
In yet another aspect, this invention comprises a brush for an electric motor, consisting essentially of a contact for contacting a commutator, a power connector (PIG), an LC noise filter for deterring noise signals received by the contact from reacting the power connector, and a matrix supporting the contact, power connector, and LC noise filter.
In still another aspect, this invention comprises a method of constructing a brush for a motor, comprising the steps of providing a contact for contacting a commutator, and attaching a filter, comprising an inductor and a capacitor, to the contact in a manner which precludes usage either the inductor or the capacitor individually in another radio-frequency circuit.
In yet another aspect, this invention comprises a brush assembly for an electric motor, comprising a hollow brush box containing ferrite material distributed within the material of which the box is constructed, and a brush slidably contained within the box.
In yet another aspect, this invention comprises a brush assembly for an electric motor, comprising a generally dumbbell-shaped brush, having two ends of large diameter, connected by a shaft of small diameter, a mass of ferrite-bearing material surrounding the shaft, a brush box within which the brush is slidably engaged, which includes a conductive region which is capacitively coupled to ground, and an insulative region.
In still another aspect, this invention comprises a brush assembly for an electric motor, comprising a generally dumbbell-shaped brush, having two ends of large diameter, connected by a shaft of small diameter, a mass of ferrite-bearing material surrounding the shaft, a brush box within which the brush is slidably engaged, which includes a conductive region, and an insulative region.
A further object of the invention is to provide an electric motor in which brushes contain filter inductors.
A further object of the invention is to provide a brush for an electric motor which contains a filter inductor integrally manufactured therein, or attached thereto.
A yet further object of the invention is to provide a brush for an electric motor which contains both a filter inductor and a filter capacitor, integrally manufactured therein.
Further objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims.